Electrophoresis gel plate assemblies conventionally comprise a glass-like support on either side of a gel slab in which the electrophoresis takes place. To control temperature build-up in the slab, thermal metallic plates have been provided on the back side of at least one of the supports, for example as described in Japanese Kokai No. 60/215785. The support with the thermal plate is usually considered to be the back support. Although such assemblies have been found to operate satisfactorily, it is a problem with such assemblies that the back support glass or enamel can become damaged. Such damage, i.e., scratches, tend to interrupt the smooth surface to create an artifact that at best confuses the reading of the electrophoresed bands and at worst interferes with the movement of the bands through the gel. Damage can also lead to a direct electrical contact with the thermal plate, producing a burn. As a result, the back support has to be discarded if it is accidentally scratched, and replaced with a new one, including a new thermal plate.
Therefore, there has been a need prior to this invention to avoid replacing the entire back support, including the metallic plate, just because the glass-like material has become scratched.